Flavanols and their dimer procyanidins as well as methylxanthines are two groups of secondary metabolites that are present together in chocolate and green tea. Flavanols and procyanidins are desired ...compounds in food because of their potential for prevention of cardiovascular diseases. Methylxanthines have influence on the central nervous system increasing attention, physical performance and muscular recovery etc, however in high doses especially caffeine can cause shivering, wakefulness, heart beating and even delirium. HPLC is the most usable chromatographic technique for the separation of flavanols, procyanidins and methylxanthines. However, the separation of flavanols and dimer procyanidins needs about an hour on ordinary C1B columns despite of gradient elution [1]. Therefore, the aim of our work was to developa faster HPlC method for the separation of flavanols, procyanidins and methylxanthines in one run. lnstead of the ordinary RP column the core-shell column was used. Core-shell columns are a new generation columns with 2.6 or 2.7 iJm particle sizes which give better resolution as well as shorter separation time and can be employed on the HPLC system. Mobile phases based on acetonitrile-water or methanol-water with addition of acetic or formic acid were tested. The flow rate and the temperature were also optimised. The baseline separation of five flavanols (epigallocatechin, catechin, epicatechin, epicatehin gallate), three procyanidins (procyanidin Bl, B2 and A2), three methylxanthines (theobromine, theophylline and caffeine) was achieved in 10 minutes on C1B Kinetex column (100 x 4.6 mm; 2.6 IJm particle size; Phenomenex, Torrance, USA) by using acetonitrile and water with acetic acid in both solvents in gradient mode. The run time for routine analysis was extended to 5 more minutes for column elution and conditioning. The optimised HPLC method was used for analysing chocolate samples previously c1eaned by solid-phase extraction.
It was not necessary to add the material to the shelf.
Bibliographic material was successfully added on shelf.
Adding bibliographical material on shelf was not successful.
Material is already on the shelf.
Permalink
URL:
Impact factor
Access to the JCR database is permitted only to users from Slovenia. Your current IP address is not on the list of IP addresses with access permission, and authentication with the relevant AAI accout is required.
Year
Impact factor
Edition
Category
Classification
JCR
SNIP
JCR
SNIP
JCR
SNIP
JCR
SNIP
Impact factor
Select the library membership card:
DRS,
in which the journal is indexed
Database name
Field
Year
Links to authors' personal bibliographies
Links to information on researchers in the SICRIS system
Subject headings in COBISS General List of Subject Headings
Select pickup location
The material from the parent unit is free. If the material is delivered to the pickup location from another unit, the library may charge you for this service.
